package com.ustcinfo.study.mr.fangmingchuan;

import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IntWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.Mapper;
import org.apache.hadoop.mapreduce.Reducer;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;

import java.io.IOException;


public class MyWorldCount {
    private static class MyMapper extends Mapper<Object, Text, Text, IntWritable> {
        private static final IntWritable count = new IntWritable(1);

        @Override
        protected void map(Object key, Text value, Context context) throws IOException, InterruptedException {
            String line = value.toString();
            String[] arr = line.split(" ");
            for (int i = 0; i < arr.length; i++) {
                Text word = new Text();
                word.set(arr[i]);
                context.write(word, count);
            }
        }
    }

    private static class MyReducer extends Reducer<Text, IntWritable, Text, IntWritable> {
        @Override
        protected void reduce(Text key, Iterable<IntWritable> values, Context context) throws IOException, InterruptedException {
            int sum = 0;
            for (IntWritable val : values) {
                sum += val.get();
            }
            context.write(key, new IntWritable(sum));
        }
    }

    public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException {
        Job job = Job.getInstance();
        job.setJobName("sg_word_count");
        job.setJarByClass(MyWorldCount.class);
        job.setMapperClass(MyMapper.class);
        job.setCombinerClass(MyReducer.class);
        job.setReducerClass(MyReducer.class);
        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);
        
		FileInputFormat.addInputPath(job, new Path(args[0]));
        FileOutputFormat.setOutputPath(job, new Path(args[1]));
        
		int status = job.waitForCompletion(true) ? 0 : 1;
        System.exit(status);

    }

}
